Process for protecting a substrate with an arylsulfonamidopyridazine intumescent agent

ABSTRACT

Intumescent compositions of the invention comprise certain arylsulfonamidopyridazines, such as 3-sulfanilamidopyridazine and derivatives thereof. The intumescent agents may be employed in conjunction with additives conventionally used in intumescent compositions. For use in protecting substrates from heat and fire, the intumescent compositions may be applied to the substrate in any suitable manner, such as by electro-deposition, spraying onto an adhesive substrate, or the application of a coating composition comprising the intumescent agent.

iii? EQ'YQrQE BS EJHEEEQ Stat [111 3,769,083 M11 Oct. 30, 1973 PROCESS FOR PROTECTING A OTHER PUBLICATIONS SUBSTRATE WITH AN RYLVSU O QQPYR A INE INTUMESCENT AGENT Inventor: Shirley H. Roth, Highland Park, NJ.

[73] Assignee: V Cities Service Company, New York,

Northey, Sulfonamides," pp. 31, 32, 79, 80 (1948).

Primary Examinerwilliam D. Martin Assistant ExaminerHarry J. Gwinnell Attorney-Richard S. Strickler et a1.

[57] ABSTRACT intumescent compositions of the invention comprise certain arylsulfonamidopyridazines, such as 3- sulfanilamidopyridazine and derivatives thereof. The intumescent agents may be employed in conjunction with additives conventionally used in intumescent compositions. For use in protecting substrates from heat and tire, the intumescent compositions may be applied to the substrate in any suitable manner, such as by electro-deposition, spraying onto an adhesive substrate, or the application of a coating composition comprising the intumescent agent.

4 Claims, No Drawings PROCESS FOR PROTECTING A SUBSTRATE WITH AN ARYLSULFANAMIDOPYRIDAZINE INTUMESCENT AGENT BACKGROUND OF THE INVENTION 1. Field of the invention This invention relates to intumescent compositions and more particularly relates to such compositions containing a one-component intumescent agent.

2. Description of the Prior Art It is known that a substrate may be protected from heat and fire by the application of an intumescent composition. Intumescent compositions of the prior art usually contain an intumescent agent having at least three components; i.e., a carbonific, a spumific, and a catalyst; and they are typically characterized by the disadvantages of high cost, low spreading rate, relatively poor efficiency, poor water resistance, and poor weatherability.

As disclosed in U. S. Pat. No. 3,535,130, it has already been discovered that a one-component intumescent agent has advantages over multicomponent intumescent agents. However, the intumescent agents of the patent have poor adherence to substrates and have an undesirable degree of moisture sensitivity.

SUMMARY OF THE INVENTION An object of this invention is to provide a novel class of one-component intumescent agents.

Another object is to provide such intumescent agents having good efficiency and a low level of moisture sensitivity.

These and other objects are attained by using as intumescent agents compounds corresponding to the formula:

wherein Ar is a divalent aromatic residue, R is hydrogen, hydrocarbon, halohydrocarbon, or acyl, and R" is a pyridazyl or substituted pyridazyl radical.

DESCRIPTION OF THE PREFERRED I EMBODIMENTS The intumescent agents of the invention may be any compounds corresponding to the above formula. However, they are preferably compounds wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof. When the aromatic ring bears organic substitutents, it is usually preferred that these substituents contain 1-5 carbon atoms. When there are halo substituents, it is usually preferred that they be chloro or bromo. It is also preferred that the aromatic ring have at least one free reactive position.

As indicated above, R of the formula may be hydrogen or a hydrocarbon, halohydrocarbon, or acyl radical, e.g., an alkyl, chloroalkyl, or bromoalkyl radical containing 1-5 carbon atoms, a phenyl, chlorophenyl, or bromophenyl radical, or an aliphatic or aromatic acyl radical.

R" is preferably a pyridazyl radical, but it may bear one or more substituents if desired. The substituted zine pyridazine, 3-( 3,4-diaminobenzenesulfonamido)- pyridazine, 3-( 4-amino-2-acetamidobenzenesulfonamido)-pyridazine, 3-(2-amino-4-nitrobenzenesulfonamido )pyridazine 3 4-methylaminobenzenesulfonamido )pyridazine, 3-( 4-chloroethylaminobenzenesulfonamido )pyridazine, 3-( 4- bromomethylaminobenzenesulfonamido )pyridazine 3-(4-phenylaminobenzenesulfonamido )pyridazine, 3- A [4-(p-chlorophenylamino)-benzenesulfonamido]- pyridazine 3-[ 4-( p-bromophenylamino )-benzenesulfonamido1pyridazine, 3-( p-acetamidobenzenesulfonamido )pyridazine 3 p-benzamidobenzenesulfonamido)-pyridazine, 6-chloro-3- sulfanilamidopyridazine 6-bromo-3 sulfanilamidopyridazine, 6-ethylcarboxy-3- sulfanilamidopyridazine, 6-hydroxy-3- sulfanilamidopyridazine, 6-ethylthio-3- sulfanilamidopyridazine 6-( 4- aminophenylsulfonamido)-3-sulfanilamidopyridazine,

6-methyl-3-sulfanilamidopyridazine, 6-methoxy-3- sulfanilamidopyridazine 6-ethoxy-3 sulfanilamidopyridazine, 6-phenyl-3 sulfanilamidopyridazine, 3- sulfanilamidobenzopyridazine, the corresponding naphthalene compounds, etc. When not readily available, these compounds may be prepared by known techniques.

For use in protecting a substrate from heat and fire, the intumescent agents of the invention may be applied in any suitable manner, e.g., electrodeposition, spraying of powdered intumescent agent onto an adhesive substrate, etc. However, it is usually preferred to compound the intumescent agent with a binder, e.g., nitrocellulose, and optionally also with one or more of the other ingredients conventionally used in intumescent compositions, e.g., stabilizers, dispersing agents, pigments, driers, biocides, anti-foamers, thickeners, protective colloids, fillers, blowing agents, etc.; disperse the composition in a suitable liquid medium, e.g., water weight and an intumescent agent/binder weight ratio of about 0.075-14/1 to deposit a coating having a dry thickness of about 0.00l0.75 inch.

The intumescent agents of the invention are efficient, have low moisture sensitivity, and intumesce to form foams having good volume, cell structure, and adherence to substrates, such as wood, metal, and plastics. They are also useful as flame retardants in normally flammable compositions.

The following example is given to illustrate the invention and is not intended as a limitation thereof.

EXAMPLE I l. A process for protecting a substrate from heat and fire which comprises applying thereto an intumescent composition comprising as the intumescent agent a compound corresponding to the formula:

RHNAr-N H R wherein Ar is a divalent aromatic residue, R is hydrogen, hydrocarbon, halohydrocarbon, or acyl, and R" is a pyridazyl or substituted pyridazyl radical.

2. The process of claim 11 wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alltoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof.

3. The process of claim 1 wherein R" is a pyridazyl radical or a halo or allroxy derivative thereof.

4. The process of claim 11 wherein the intumescent x UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,769,083 Dated October 30, 1973 Inventor(s) hirley H. Roth It is certified that error appears in the above-identified patent and that said Letters Patent are' hereby corrected as shown below:

Column 1, line 38, the portion of the formula reading "NHR" should read NHR" Column 4, line 8, the portion of the formula reading "NHR" should read RHNAr-s-NHR" Signed and sealed this 25th day of June 197E.

(SEAL) Attest:

EDWARD M.FLEICHER,JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents 

2. The process of claim 1 wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof.
 3. The process of claim 1 wherein R'''' is a pyridazyl radical or a halo or alkoxy derivative thereof.
 4. The process of claim 1 wherein the intumescent agent is 3-sulfanilamidopyridazine. 